Rollup

4.60.1 · active · verified Sat Apr 18

Rollup is a next-generation ES module bundler that compiles small pieces of code into larger, more complex libraries or applications. It uses the standardized ES module format, allowing for efficient tree-shaking and optimized bundles. The current stable version is 4.60.1, and it maintains an active release cadence with frequent bug fixes and minor feature additions.

Common errors

```
Error: You must supply a name for UMD bundles
```
cause The `umd` output format requires a global variable name for the bundle to attach to.

fix Add the `--name "myBundleName"` option when using `output.format: 'umd'` or `rollup --format umd`.
```
Error: The generated bundle contains paths that would leave the output directory.
```
cause Rollup's new validation prevents output files from being written outside the specified `output.dir`.

fix Adjust your output configuration (`output.assetFileNames`, `output.chunkFileNames`) to ensure all paths are relative and contained within the `output.dir`.
```
rollup: command not found
```
cause The Rollup CLI is not installed globally or not accessible in the current shell's PATH.

fix Install Rollup globally with `npm install --global rollup` or run it locally using `npx rollup`.

Warnings

deprecated Returning import attributes from `load` or `transform` hooks is deprecated and will not be supported in Rollup 5.
Fix: Refactor plugins to avoid returning import attributes from `load` or `transform` hooks.
breaking Rollup now throws an error if the generated bundle contains paths that would escape the specified output directory.
Fix: Ensure all generated asset and chunk paths remain within the configured output directory.
gotcha Rollup requires Node.js v18.0.0 or higher.
Fix: Upgrade your Node.js environment to version 18.0.0 or newer.
gotcha Versions prior to 4.60.1 could incorrectly drop side effect imports due to a caching issue.
Fix: Upgrade to Rollup v4.60.1 or higher to ensure all side effects are correctly preserved.

Install

npm install rollup npm
yarn add rollup yarn
pnpm add rollup pnpm

Imports

rollup
wrong:
```
const { rollup } = require('rollup');
```
correct:
```
import { rollup } from 'rollup';
```
Rollup's programmatic API is primarily designed for ES Modules.

Quickstart

This quickstart demonstrates using Rollup's JavaScript API to bundle an entry file (`src/main.js`) into an immediately invoked function expression (IIFE) for browser usage, including sourcemaps and common plugins for resolving Node.js modules and converting CommonJS.

import { rollup } from 'rollup';
import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';

async function build() {
  const bundle = await rollup({
    input: 'src/main.js',
    plugins: [resolve(), commonjs()]
  });

  await bundle.write({
    file: 'dist/bundle.js',
    format: 'iife',
    name: 'myBundle',
    sourcemap: true
  });

  console.log('Bundle created successfully!');
}

build().catch(console.error);

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